1. Technical Field
The present disclosure relates to an electrosurgical system and method. More particularly, the present disclosure relates to a system and method for reducing the risk of alternate site tissue damage by reducing the overall leakage current in the electrosurgical system.
2. Background of Related Art
Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, ablate, or coagulate tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of the surgical instrument held by the surgeon and applied to the tissue to be treated. A patient return electrode is placed remotely from the active electrode to carry the current back to the generator.
In bipolar electrosurgery, one of the electrodes of the hand-held instrument functions as the active electrode and the other as the return electrode. The return electrode is placed in close proximity to the active electrode such that an electrical circuit is formed between the two electrodes (e.g., electrosurgical forceps). In this manner, the applied electrical current is limited to the body tissue positioned between the electrodes. When the electrodes are sufficiently separated from one another, the electrical circuit is open and thus inadvertent contact of body tissue with either of the separated electrodes does not cause current to flow.
Tissue damage may occur when either the ground or return cable connecting the return electrode plates to the RF source is broken or the patient moves out of contact with the return electrode. When either of these conditions occur and there is also another or secondary ground contact to the patient, current will flow through the secondary ground contact and cause localized tissue damage to the patient at the point where the secondary ground contacts the patient. Such secondary ground may be created by monitoring electrodes connected to the patient, grounded adjacent metallic equipment, etc. In other words, when the normal ground return is broken or separated from the patient, the electrical energy flowing through the active electrode seeks alternate current paths if they exist. Because these other paths usually contact the patient over small areas, the current densities may be very high, which may result in tissue damage.
Conventional electrosurgical generators isolate the RF output by use of a transformer. The capacitive coupling of this transformer controls the amount of leakage current that flows from the RF output to the ground contact and back to the generator. However, since only the transformer is used to isolate the output, the leakage current may have an alternate path to the internal board grounds of the generator and may, therefore, cause tissue damage.